Known Differences between PADs and TCPs
---------------------------------------

a) Prompts
----------
     There is no way in the X29 protocol to support 'prompts' as we know
them on EMAS.   It is not specifically the PAD which stops their use but
the X29 protocol itself.

b) Screen Editing
-----------------
     From the work done by Duncan, it is obvious that SSMP will fit inside a
BBC Micro or other similar micros.   From this, it ought to be possible to
produce a reasonable screen editor for EMAS.  

     In addition, it would appear that a modified version of VECCE will run
on an Esprit on a PAD although work is required on the editor in EMAS to
recover all the functions.

c) Interrupts
-------------
     There was a problem at the beginning but all interrupts can now be used 
and the INT: 'prompt' raised by typing CTRL P then B which is only just worse
than typing ESC.

d) X-Talk
---------
     Source files can be transferred from the PAD successfully.   Binary (ie
8 bit) files can't be transferred from the PAD to EMAS.   In the short term it
will be necessary for micro support to encode binary files as text before
transmission and then encode them.   In the longer term (end 84?) full 8 bit
transmission should be available with an implementation of FTP on an asynchronous
Transport Service in the longer term.

e) Into Support
---------------
     We will not be able to poll PADs in the same way as TCPs although we will
be able to determine their status.   In the coming PAD software we will be able
to interrogate them for statistics etc although it will be too expensive on a
2/3 minute basis.

f) TAB
------
     It is possible to select on a call basis whether CENTR I (tab) is sent to
the host or a number of spaces.   The number of spaces is selectable on a bi
terminal basis and it would be possible to have two host names set up (one with
tab, the other spaces) if a user required the character CTRL I to reach the
host.   Alternatively, EMAS could do sensible things with Tabs.

g) Dial-up
----------
     We appear to have a problem with 1200 baud dial-up that will require further
investigation.   If absolutely necessary a PDP11 could be used as a 'front end'
to the PAD for dial-up use only.


                                                      Brian Gilmore
                                                      2nd May 1984.